What effects does the solar eclipse have on the weather?

The solar eclipse has many effects on people's lives, among which, except for short-wave communication, the most obvious one is the impact on the weather.

When a solar eclipse occurs, Lang Lang Gan Kun suddenly turns to dusk or even night, which often causes mental fear and anxiety of the ancients. In fact, at this time, the ground weather is indeed undergoing abnormal or even drastic changes. However, this kind of ground weather change astronomy has not been studied, and it does not belong to the normal business scope of meteorological departments, so there are few research reports in history.

1On June 20th, 955, there was a solar eclipse in Asia. Although the total solar eclipse area is located in the latitude of Xisha and Zhongsha sea areas in China, the food intake in the area south of 30 north latitude in China is above 50%, and the food intake in South China and Southwest China south of the Tropic of Cancer is above 75% (100% during the total solar eclipse).

The solar eclipse occurs not only near the summer solstice when the sun is highest all the year round, but also around noon when the sun is highest in a day, so it is an extremely rare observation opportunity. At that time, central weather bureau (now China Meteorological Bureau) asked the Southern Meteorological Observatory to observe the solar eclipse.

The fly in the ointment is that the southern part of China has entered the rainy season on June 20, and it rained in many places. Only Guangdong and Hainan have good weather conditions, so the meteorological change of solar eclipse is also the most significant, which is manifested in the following characteristics:

(1) When a solar eclipse occurs, the temperature will drop sharply. Looking up the reports of the Southern Meteorological Observatory in China at that time, it was found that dozens of meteorological stations had meteorological observation records of solar eclipse.

The temperature change is most significant in sunny Shenzhen. Four minutes before the solar eclipse, that is, 10: 32, the temperature in Shenzhen was 30.2℃. With the increase of food fraction, the temperature changed abnormally from rising to falling, and it dropped to 26.3℃ during the extreme eclipse (12: 08+0 1: 00), that is, it dropped by 3.9℃. After a full meal, the temperature rose again, and reached 29.2℃ at the last contact (13: 29), which still did not reach the temperature before the solar eclipse.

(2) The change of ground temperature is greater than that of air temperature. This is because the temperature rises during the day and the cold and heat sources for the temperature drop at night are all on the ground.

Unfortunately, there was no observation report on the surface soil temperature in Shenzhen at that time. Take Dan County in Hainan as an example. The temperature in xian county was 32.4℃ during the first solar eclipse, and 30.2℃ during the worst solar eclipse. That is, because there were clouds in the sky, the temperature only dropped by 2.2℃ during the solar eclipse. However, the ground temperature plummeted from 42.9℃ to 32.5℃ (it rose to 5 1.4℃ after the last contact), that is, plummeted 10.4℃! It is estimated that the change of ground temperature in Shenzhen at that time was greater than that in Danxian.

(3) The depth of the solar eclipse temperature change is only slightly deeper than10cm. It is commendable that the qionghai city Meteorological Observatory measured the temperature every four minutes during the eclipse, which made us know that the lowest temperature during the eclipse did not occur at midnight, but about half an hour after the eclipse, although the temperature was only 0.2℃ lower than midnight.

The underground temperature measurement in Qionghai every 4 minutes also reveals that the surface temperature drop caused by solar eclipse generally only affects the place slightly deeper than 10 cm, because soil is a poor conductor of heat. At the depth of underground 15 cm, the temperature will not drop during the eclipse.

(4) The relative humidity of air increased obviously. During the solar eclipse, the relative humidity of the ground atmosphere also changed dramatically. Originally, under the normal circumstances without solar eclipse, the highest temperature appeared before the afternoon (about 14), and the relative humidity kept decreasing regularly (because the temperature kept rising), but during the solar eclipse, the relative humidity increased due to the decrease of inverse temperature.

For example, the humidity in Shenzhen suddenly rose from 765,438+0% in the initial deficit to 88% when food was consumed in large quantities. After overeating, it returned to normal, and the last contact dropped to 78%, but it was still higher than before.

(5) The eclipse turned noon into dusk and moonlit night. It is interesting to describe the changes in the sky during the solar eclipse. For example, the Guangzhou Meteorological Observatory recorded: "When the food is heavy, the brightness of the sun is very weak, about 80% weaker than usual, and the sun shines on people without the usual feeling of heat. The whole sky is like a moonlit night. "

Guangxi Baise reported that "the ground is yellow-brown". Nanning, Guangxi and Beihai describe the sky with "yellow and gloomy" and "the sun is as weak as dusk" respectively. Lijiang, Yunnan, recorded the change of cloud color, saying that the altocumulus is translucent, "the cloud color is light black and uneven".